The prior art embraces units for filling containers with liquid or powder products, equipped with a carousel carrying a plurality of devices designed to support the containers, each associated with a respective dispensing device by which a predetermined quantity of material is made to fall into a container placed on the support device.
The operation of the single dispensing device is interlocked to respective weighing means housed in the support device and able to sense the weight of the container continuously. At a given moment during the filling step when the weighing means indicate that a predetermined weight has been reached, signifying that the container is full, the dispensing device will terminate the flow of liquid or powder material, for example by closing a shut-off valve on a feed duct through which the material is dispensed.
As a general rule, weighing means take the form of a dynamometer housed within a hollow body located beneath a pedestal on which the container is placed. The pedestal carries a plunger insertable through a hole in the top of the hollow body. Thus, the plunger is located partly within the hollow body and able to interact with the dynamometer.
Conventional units of the type outlined above are washed down periodically so as to remove any spills or splashes of the liquid or powder products with which the containers are filled. In the course of filling operations, more exactly, part of the liquid or powder product can escape from the containers and drop onto the pedestal of the support device, onto the hollow body or onto the carousel.
At the end of a given production run, accordingly, nozzles are activated to direct a washing liquid onto the carousel, especially onto those areas where the spills or splashes are most heavily concentrated.
The washing process in question is a cause of major drawbacks however, due to the infiltration of washing liquid through the hole in the hollow body.
In effect, the dynamometer components include a piezoelectric material, and electronic parts that are easily damaged if brought into contact with a liquid.
Furthermore, the presence of the washing liquid on the plunger and in the hole of the hollow body can impede the correct movement of the selfsame plunger toward and away from the weighing means, with the result that errors occur during the step of weighing the container. Over time, in fact, moving mechanical parts of the support and weighing device can be rusted by any liquid sediments that linger.
The object of the present invention is to provide a supporting and weighing device for containers that will be unaffected by the drawbacks mentioned above.
In particular, the object of the present invention is to provide a supporting and weighing device for containers, which can undergo washing operations without suffering damage.